Engine Tune-Up
DETROIT DIESEL
b. Remove the high-speed spring from the high-
9.
Position the remaining injector rack control
speed spring plunger and add or remove shims
levers as outlined in Steps 6 and 7.
(Fig. 6) as required to establish the desired
engine no-load speed.
10.
Connect the fuel rod to the injector control tube
lever.
NOTE For each .010" shim added, the engine
11.
Turn the idle speed adjusting screw in until it
speed will be increased approximately 10 rpm.
projects 3/16" from the lock nut to permit starting the
engine. Tighten the lock nut.
c. Install the high-speed spring on the plunger and
install the spring assembly in the governor
12.
Use a new gasket and replace the valve rocker
housing.
Install the spring retainer in the
cover.
governor housing and tighten it securely.
Adjust Maximum No-Load Engine Speed
d. Start the engine and recheck the engine no-load
All governors are properly adjusted before leaving the
speed. Repeat the procedure as necessary to
factory.
However, if the governor has been
establish the no-load speed.
reconditioned or replaced, and to ensure the engine
speed will not exceed the recommended no-load speed
Adjust Idle Speed
as given on the engine option plate, set the maximum
With the maximum no-load speed properly adjusted,
no-load speed as follows:
adjust the idle speed as follows:
TYPE A GOVERNOR SPRINGS (Fig. 6):
1.
With the engine running at normal operating
temperature and with the buffer screw backed out to
1.
Loosen the lock nut (Fig. 5) and back off the
avoid contact with the differential lever, turn the idle
high-speed spring retainer approximately five turns.
speed adjusting screw (Fig. 7) until the engine is
operating at approximately 15 rpm below the
2.
With the engine at operating temperature and
recommended idle speed.
no-load on the engine, place the speed control lever in
the full-fuel position.
Turn the high-speed spring
NOTE: The recommended idle speed for non-
retainer IN until the engine is operating at the
EPA certified engines is 500-6 rpm, but may
recommended no-load speed.
vary with special engine applications.
The best method of determining the engine speed is
2.
Hold the idle speed adjusting screw and tighten
with an accurate tachometer.
the lock nut.
3.
Hold the high-speed spring retainer and tighten
the lock nut.
TYPE B GOVERNOR SPRINGS (Fig. 6):
1.
Start the engine and after it reaches normal
operating temperature, remove the load from the engine
2
Place the speed control lever in the maximum
speed position and note the engine speed.
3.
Stop the engine and, if necessary, adjust the no-
load speed as follows:
a. Remove the high-speed spring retainer, high-
speed spring and plunger.
Fig. 7 - Adjusting Engine Idle Speed
CAUTION: To prevent the low-speed spring and
cap from dropping into the governor, be careful
not to jar the assembly while it is being
removed.
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